T wave inversion in experimental myocardial ischemia and sympathetic nerve stimulation

In open-chest dogs, T wave changes were recorded following coronary occlusion and sympathetic nerve stimulation. Recording of suction electrograms was made to study their genesis. Not only after release but immediately after introduction of coronary occlusion, T wave was inverted significantly associated with QT prolongation in sites with prolonged excitation duration in suction electrogram. Sympathetic nerve stimulation also produced T inversion followed by rapid reversion to positive T wave, which was apparently analogous to ischemic changes in electrophysiological aspects. However, the underlying mechanisms were thought to be much different.